Role of Fungicides, Application of Nozzle Types, and the Resistance Level of Wheat Varieties in the Control of Fusarium Head Blight and Deoxynivalenol

Abstract

Fungicide application is a key factor in the control of mycotoxin contamination in the harvested wheat grain. However, the practical results are often disappointing. In 2000-2004, 2006-2008 and 2007 and 2008, three experiments were made to test the efficacy of fungicide control on Fusarium Head Blight (FHB) in wheat and to find ways to improve control of the disease and toxin contamination. In a testing system we have used for 20 years, tebuconazole and tebuconazole + prothioconazole fungicides regularly reduced symptoms by about 80% with a correlating reduction in toxin contamination. Averages across the years normally show a correlation of r = 0.90 or higher. The stability differences (measured by the stability index) between the poorest and the best fungicides are about 10 or more times, differing slightly in mycotoxin accumulation, FHB index (severity) and Fusarium damaged kernels (FDK). The weak fungicides, like carbendazim, were effective only when no epidemic occurred or epidemic severity was at a very low level. Similar fungicide effects were seen on wheat cultivars which varied in FHB resistance. In this study, we found three fold differences in susceptibility to FHB between highly susceptible and moderately resistant cultivars when treated with fungicides. In the moderately resistant cultivars, about 50% of the fungicide treatments lowered the DON level below the regulatory limit. In the most susceptible cultivars, all fungicides failed to reduce mycotoxin levels low enough for grain acceptance, in spite of the fact that disease was significantly reduced. The results correlated well with the results of the large-scale field tests of fungicide application at the time of natural infection. The Turbo FloodJet nozzle reduced FHB incidence and DON contamination when compared to the TeeJet XR nozzle. Overall, the data suggest that significant decreases in FHB incidence and deoxynivalenol contamination in field situations are possible with proper fungicide applications. Additionally, small plot tests can be used to evaluate the quality of the field disease and toxin production.

Quantifying the Effects of Fusarium Head Blight on Grain Yield and Test Weight in Soft Red Winter Wheat

“…However, the development of such models requires knowledge, understanding, and quantitative estimates of losses caused by this disease, as well as quantitative estimates of the effects of different management strategies on FHB, DON, grain yield, test weight, and their relationships. Some work has been done to characterize and quantify some of these effects in detail (6,27,33,34,36,38,40,47,49) but less emphasis has been placed on quantifying the FHB-yield and FHB-test weight relationships. There are numerous reports of yield loss due to FHB in the literature but, in most cases, specific quantitative information pertaining to the FHB-yield relationship is not provided (30).…”

DON Occurrence in Grains: A North American Perspective

“…Additionally, combining improved cultivars with fungicides and optimal spray technology at flowering provides the best management practice for reducing the risk of DON in wheat and barley, as demonstrated by Wegulo et al (84) (Fig. 10) and others (106)(107)(108).…”

Comprehensive quantification of N-glycoproteome in Fusarium graminearum reveals intensive glycosylation changes against fungicide

“…Developing new FHB manage method was urgent because chemical fungicides that have long been used for the management of FHB have met many problems that such as not friendly to environment and human health, stimulate the pathogen's production of mycotoxins [16], or failed to reduce mycotoxin levels low enough for grain acceptance [17]. Antifungal volatiles (AVs) was a mixture of microbial volatiles against F. graminearum that produced by marine actinomycete Streptomyces sp.…”